This Tenkaichi 3 MOD video shows Vegeta SSJ and Goku SSJ fuse into Super Gogeta through the fusion dance.Normally, it's impossible for Goku and Vegeta to do the fusion dance when they are transformed in super saiyans in Dragon Ball Z Budokai Tenkaichi 3 but in this mod video, they do it like that in this state :)

Also, in this video, Super Gogeta destroys Janemba and ends the fight just like in the Dragon Ball movie "Fusions" :http://www.youtube.com/watch?v=6-uyC2ImEeA&list=PLb-9PYpuuDKxdpTCTafCcQs1VD5Yw6QJR